A method for exploring and finding a subterranean hydrocarbon reservoir by modeling of temperature and/or thermal anomalies within a geologic volume of the earth's crust. The geologic volume is subdivided into a plurality of laterally disposed and aligned, and vertically disposed and aligned, volumetric cells. Geologic properties are assigned for each of the volumetric cells, and a normal gradient temperature is determined and generated for the geologic volume. An x, y, z temperature is assigned for each volumetric cell based on the normal gradient temperature of the geologic volume. A hypothetical hydrocarbon reservoir is disposed in the geologic volume by varying the geologic properties of some of the plurality of volumetric cells; and a true x, y, z temperature is computed for each volumetric cell caused by the hypothetical hydrocarbon reservoir. A true hydrocarbon reservoir in the geologic volume is determined from the true x, y, z temperature of each volumetric cell.